1. Field of the Invention
The present invention relates generally to printing presses and more particularly to a device and method for splitting a stream of printed products.
2. Background Information
Web printing presses print a continuous web of material, such as paper. The continuous web then is cut in a cutting unit so as to form book blocks. These book blocks can be sections of a newspaper, for example. In order to process the book blocks, for example to perform a trimming operation, it is often desirable to slow the product stream. This may be accomplished by splitting the product stream and then to decelerating the resultant split product streams. This often requires a large amount of floor space.
U.S. Pat. No. 3,702,129 describes a mechanical book clamp which can accommodate various book thicknesses. A chain drive can be used to move the clamps along a desired path.
U.S. Pat. No. 5,740,900 discloses an apparatus for splitting a product stream into an A stream and a B stream. The signatures are gripped by grippers, and alternating grippers rotate to split the product stream. This device requires a large amount of floor space to perform the split, and performs only an A/B split.
An object of the present invention is to provide for a device and method for splitting a printed product stream, such that the amount of floor space required for the split is reduced. An additional or alternative object of the present invention is to be able to split the printed product stream into more than two substreams.
The present invention provides a method for splitting a product stream including the steps of delivering a plurality of products to a circular path, transferring a first product of the plurality of products inwardly from the circular path to a first substream, and transferring a second product of the plurality of products inwardly from the circular path to a second substream.
By using the circular path and inward transferring, the splitting can be accomplished in a vary small amount of floor space, i.e. with a small footprint.
A single transfer device may perform both the transferring of the first product and the transferring of the second product. The method also may further comprise transferring a third product of the plurality of products inwardly from the circular path to a third substream and transferring a fourth product inwardly from the circular path to a fourth substream. The first substream, the second substream, the third substream and the fourth substream then may be located in a circular arrangement ninety degrees apart. In such an arrangement, the first product may be received by a transfer device attached to a support and delivered to the first substream after a ninety degree rotation of the support. The transfer device preferably rotates 180 degrees during the ninety degree rotation of the support.
The first and second substreams preferably move downwardly, which permits for a minimum of floor space use.
The present invention also provides a device for splitting a product stream comprising a support rotatable about a central axis, the support having an outer circumference and an inner circumference, and at least one transfer device attached to the support for receiving products of the product stream. The transfer device has a first position for receiving a first product of the products at the outer circumference and a second position for delivering the first product to a substream at the inner circumference.
The at least one transfer device preferably includes four transfer devices. The support may include a hub and four arms extending from the hub. A first of the at least one transfer device preferably is located at an end of one of the four arms, the end being located away from the hub. The support also may include a hub and eight arms. In the second position the transfer device is capable of receiving a second product of the products at the outer circumference.